Guide bar attachment



H. O. CADMAN GUIDE BAR ATTACHMENT Nov. 25, 1952 5 Sheets-Sheet 1 FiledNov. 9, 1949 Nvsm-rom/ @-lcxva .fel 0. CCldYnC/m fw. mg

Nov. 25, 1952 Filed NOV. 9, 1949 H. O. CADMAN GUIDE BAR ATTACHMENT 3Sheets-Sheet 2 INVBNTOY`, QJClr'oId 0. Codmm M ag,

Nov. 25, 1952 H. o. cADMAN GUIDE BAR ATTACHMENT 3 Sheets-Sheet 5 FiledNov. 9. 1949 A41 wm VIL NVD N'TY5`-, WQY'Q d 0. Cox dma n dum, @5M MJ,W44.

Patented Nov. 25, 1952 UNITED STATES PATENT OFFICE 2,618,910 BARA'r'r'Aonn/NT Harold-0. Cadinan, Rockton; lll.;g.assignor,' by

.msn'e assignments, to Gard-ner Machine Com'- pany,-a^crporationofIllinois Atpiiatit Novf 9, 1949, "seal-'N5'. '126,317.6 a claims. (ci.51--151L-iy The present' invention pertains generally vtor through thevwork -zone` of Va'grin'd lingmachine,-

resort is commonly had vto lthe* -use of a pai-r of laterally spacedguide bars having a thickness Asubstantially less thantlied-istance'between the abrasive wheels. The thicknes'softhe guidebary in such instances may run as low as '22' Under normaloperating'conditions, even vslight contact between they abrasive wheelsand -e'ither of such thin guide bars would produce sufficient frictionalheat to 'progressively distort the bar, resulting almost immediately inthe severing of the bar with consequent spillage-of the workpieces andshutdown of 'the machine. Heretofore, it has been customaryto adjustablyattach the guide lbars to a pair of rigidl posts,one-be-v ing locatednear thev entrance `and the other near the exit ofthe lgrinding- Zo'ne'.The initiala'dj-ustrnent is made such a i-n-an'ner' that the guidebarsare tensioned -by tlie'inherent spring ofI these posts; Under high speedoperation,

however, considerable'heating of the guidebars occurs and causes them`to expand proportionately. Forexample, a guide bar 26" in length mayrise from room temperature to 300 F. during the grinding operation,resulting ina total linear expansion of as much a'.050 Since thespringiness of the rigid supportingposts' is normally insuinc'ent toabsorb this amount of expansion,

the tension of the guide bars' tends to slack on to an undesirableextentv consequent danger of contact with the grinding wheel andseverance in the manner outlined above. Moreoverfth'e conventional type'mounting arrangiement is very apt to' producel unequal tensions in theguide bars whereby one bar may remain fairly taut and the'othermayA besoslack that it ifiexes excessively'. l Y

Accordingly, one object 'of the invention is to provide a guide barattachment for av grinding machine and which willi havea' noveltensioning arrangement for the'-g'uidebars`, such-` arrangement beingsubstantially unaiected by the thermal expansion of fthe `bars incident'to operation of the machine. I

Another object is to provide`r an attachment of the' foregoingcharacterwherein thetensionl2 ing means, .after initialv ad-ustment,will maiintain the bars under .substantially equal 'tension for variousoperating conditions.

A further object is toprov'de .a bar' tensioning means of the type fse't.forth/'which will be of simple, rugged Vand economical constructionyetcapable of 'adjustment with Va high degree of nicety and precision.

'Other objects andy advantages v'will become apparent as the following-detailed description proceeds, taken in' the'light of the accompanyingdrawings wherein:

Figure 1 is a fragmentary elevation oran illustrative guide barattachment .embodying thev present invention, theabrasive wheeisiofagrinding machine and a portion of theirl housing being shownfragmentari-ly;

Fig. 2 is-a fragmentary plan View of the vdevice show-n in Fig. 1.

Figs. 3, 4 and 5 are enlarged transverseY sectional views through t-heillustra-tiveV guide bar attachment, such views being 'respectivelytaken in the plane of the lines :im-3,` 4-4 and 5 5 in Fig. 2.

Fig. 6 is an enlarged fragmentary plan View detailing one vof thespringmembers embodying the invention, togethervwith its supporting means.v

Fie- '1 is an enlarged fraementaryperspetve view showing details; o fthetensioningjspring end of the device of ll'ig v 1, one o ftheabrasivewheels being omitted for purposes of clearer illustra-1on- Fig. Sisanjenlarged iragmentary perspective View detailing in exploded; form thefastening means usedbetween one of the guide bar ends and its tensioningspring.

While the invention is susceptible of various modinca-tions randalternative onstructions, -a preferred embodiment has been shown in thedrawings and will be /describedbelow lin considerable' detail. Itsh'ouldfbeY understood, l'1`c`iwe-ve1`,` that there is' no intentiontoiifit the .intention to the specific form disclosed, 'but on thecontrary, the intention is te ctier an mkineatiohs and alternative"constructions falling within the spirit and scope of the invention as;expressed in the appended claims'.

Upon more specic reference t'oftheY drawings, it will be perceived that'there' is shown' `an' illustrative guiderar attachment in embodyingtrie invention `and comprising `a pair 'of rigid' upstanding bed-platesyl I, I2 whichstraddle'a grin: 'ng zone donned lzietweenj'av pair oania'ljl'yfspaced mountedY in any 'appropriate' manner uponv a grindingmachine, the details of which are unimportant for present purposes. Theabrasive wheels I 4, I5 are housed within a relatively heavy protectivehood I6 fixed to the base of the grinding machine and havingdiametrically opposed mounting faces Il, I8 to which the bed-plates II,I2 are rigidly attached. Running through the grinding zone and havingtheir end portions projecting through vertical slots I5 in the bedplatesI2 are a pair of spaced apart parallel guide bars 23, 2|. As indicatedin Fig. 4, the guide bars 2), 2| are of relatively thin strap stock,having a thickness which is only a fraction of the distance between thegrinding wheels I4, I5 so as to provide clearance with the latter. Whenproperly tensioned so as to eliminate any tendency for buckling orllexure, the guide bars 20, 2| define a workpiece supporting pathrunning diametrically through the grinding zone.

Workpieces such as piston ring blanks R may be fed in a procession tothe attachment I 0 by the use of an appropriate feed mechanism. Whilethe details of such a mechanism form no part of the present invention,there is shown merely for the sake of completeness certain feedmechanism guide members which terminate at the attachment I0. Asindicated in Figs. 1, 2 and 3, such members may comprise upper and lowerguide rails 22, 24, respectively disposed in alignment with upper andlower guide bars 20, 2|. Located between the rails 22, 24 but spaced instraddling relation with the path of movement of the workpieces are apair of side guides 25, 26. The latter arerigidly xed as by means ofbolts 28 to a pair of mounting flanges 29 (Fig. 3).

Each of the flanges 29 is integral with a corresponding plunger 30slidably supported in a head 3| projecting from the face of the plate I.Each of the plungers 3|), together -with its respective one of the sideguides 25, 26 may be adjusted laterally of the path ofworkpiece movementas by means of an adjusting knob 32.

For the purpose of supporting the ends of the guide bars 20, 2|projecting through the bedplate against longitudinal movement whilepermitting adjustment of the same laterally relative to each other, thebed-plate I I is formed with a flat way 34 extending vertically thereof(Fig. 3). Slidably mounted on the way 34 are a pair of anchor blocks 35which are supported by means of a common adjusting screw 3,6. The latteris journaled in ear 31 xed to the plate I I and threadedly engagesaligned bores in each of the blocks 35. The upper portion of the screw36 is threaded in the opposite sense from its lower portion.Consequently, rotation of the screw 36 by means of its adjusting knob 3Sin one direction will cause the blocks 35 to move toward each otherwhile rotation of the knob 38 in the opposite direction will cause theblocks to move away from one another. Pivotally secured as at 39 to theupper anchor block 35 is the left hand end portion of the upper guidebar (as viewed in Fig. 1). By the same token, the left hand end portion(as viewed in Fig. 1) of the lower guide bar 2| is pivotally xed to thelower anchor block 35 as at 45. When the end portions of the guide bars20, 2| have been properly positioned by shifting the anchor blocks 35through the use of the screw 36 and adjusting knob 38, the adjustmentmay be preserved by clamping the anchor blocks 35 against movement alongthe way 34. This is accomplished in the present instance by the use of aT-slot 4| eX- tending longitudinally of the way 34 and adapted toreceive the heads of clamping bolts 42 carried by the blocks 35. Each ofthe bolts 42 may be clamped simply by tightening its nut 44.

In order to provide a corresponding lateral adjustment for the oppositeend portions of the guide bars 20, 2|, the bed-plate I2 is provided witha vertical way 45 similar to the way 34 (Figs. 1, 2 and 5). A pair ofanchor blocks 45 is slidably supported on the Way 45 by means of a screw41 similar to the screw 36 and rotatably mounted in ear 48 fixed to theplate I2. The blocks 46 may be sifted toward or away from one anothersimply by turning adjusting knob 49 of the screw 41 in the properdirection. To clamp the blocks 46 in a desired condition of adjustment,the way 45 has a T-slot 5|) which receives the heads of clamping bolts5| carried by the anchor blocks 45.

Means is provided for maintaining each of the guide bars 2|), 2| undersufcient tension to prevent ileXure, regardless of the degree of thermalexpansion incident to the grinding operation. This is accomplished byinterposing an individual tensioning means between one end of each guidebar and its supporting member, either directly or by the use of anappropriate mechanical connection, such means being adapted to exert asubstantially constant tension regardless of the degree of thermalexpansion in its corresponding guide bar. The opposite end of each guidebar is, of course, constrained against longitudinal movement relative tothe other supporting member. Accordingly, in the attachment I0 the endof each of the guide bars 20, 2| projecting through the bed-plate I2 isconnected to its anchor block 45 by means of a well loaded tensionspring 52 having a comparatively high spring scale. `In the presentinstance, each of the springs 52 comprises a relatively heavy bar ofresilient stock bent into a general U-shape. One arm of the spring abutsagainst its associated anchor block 45, being secured thereto as bymeans of the clamping bolt 5|. The other arm of the spring is adaptedfor attachment to the adjacent end of its corresponding guide bar. Asshown in Figs. 7 and 8, such attachment means may include an integrallug 54 of reduced cross section which extends into a slot 55 near theend of the guide bar. To preclude tearing of the metal between the slot55 and the end of the guide bar, a slotted reinforcing shoe 53 may beprovided. In attaching the guide bar to the spring 52, the shoe 53 isfirst inserted into the slot 55 and pushed toward the end of the bar.The parts are s0 proportioned that this will leave just sufcientclearance to comfortably insert the lug 54 between the bottom of theshoe 53 and the far wall of the slot 55.

By reason of the foregoing structure, it will be apparent to thoseskilled in the art that a thermal expansion or contraction in one of theguide bars of as much as .059 will produce only a slight deflection ofits spring 52. Moreover, due to the fact that the spring 52 is designedto operate in a substantially loaded condition, such deflection willhave an almost negligible effect upon the tension in the guide bar. Inaddition, if the guide bars 25, 2| have been initially set up withsubstantially equal tension, unequal expansion or contraction in thebars will have little if any effect upon their relative tensions.

To provide a convenient means for relieving the tension in the springs52 so as to facilitate assembly and disassembly of the guide barsthereon, a machine screw 56 is threaded onto each of the anchor blocks49 and passes through aligned transverse holes in the arms of eachspring 52. Tightening of the screw 56 will of course cause its head toforce the longer spring arm toward the shorter arm and the springtension force will thereupon be transferred to the screw 56. Thisarrangement normally produces sufficient deflection of each spring 52 topermit the slotted end of its associated guide bar to be readily slippedover the lug 54. Under normal operating conditions, however, the screw56 is backed off to a point where there is considerable clearancebetween its head and the spring arm (Fig. 6). Under such circumstances,the guide bar alone carries the spring tension. Where a high degree oftension is desired in the guide bars, it may be found convenient tointerpose a supplementary compression spring 58 between the arms of eachof the springs 52. In such installations, the screw 56 constitutes aconvenient guide for the spring 58.

Where the attachment I6 is mounted with its guide bars 20, 2| disposedin a substantially horizontal direction, it might be necessary to resortto side guides 59, 66 adjacent the plate l2. These elements straddle thepath of movement of the workpieces and are substantially similar to theside guides 25, 26 described earlier herein. Like the latter, the sideguides 59, 66 are carriediby plungers 6| slidably housed in heads 62projecting outwardly from the bed-plate I2. The guides 59, 60 may beadjusted as by means of knobs 6,4, similar to the knobs of the guides25, 26.

I claim as my invention:

1. The combination of a grinding machine having a work zone dei-inedbetween a pair of axially spaced abrasive wheels with a guide barattachment comprising a pair of upstanding bed-plates rigidly mountedwith one adjacent the entrance end and with the other adjacent the exitend respectively of the work zone, each of said bedplates having avertical way with a T-slot therein, two pairs of spaced apart anchorblocks, each pair being disposed to slide along the way of a respectiveone of said bed-plates, vertical adjusting screws disposed in threadedengagement with respective pairs of said blocks and adapted to positionthe blocks of either of said pairs at various selected distances apart,clamping means engageable with the T-slots for securing said pairs ofanchor blocks in desired conditions of adjustment, a pair of relativelythin normally flexible guide bars disposed in spaced relation andextending through the work zone and between said bed-plates, said guidebars being disposed in substantially perpendicular relation to thevertical Ways of said bed-plates, means pivotally securing the two endsof said guide bars adjacent one of said bed-plates to the anchor blocksof said one bed-plate, and substantially U-shaped tensioning springsconnected between the opposite ends of said guide bars and correspendingones of said anchor blocks on the other of said bed-plates, each saidspring being mounted with one leg fixed to its associated anchor blockand the other leg disposed for the application of tension longitudinallyof its associated guide bar.

2. In a guide bar attachment adapted for supporting a procession ofWorkpieces passing through the work zone of a grinding machine, thecombination of a U-shaped guide bar tensioning spring having anextension at one end thereof for insertion in a slot adjacent the end ofa guide bar, a reinforcing shoe also insertable in the slot and adaptedto abut said extension, a compression screw mounted transversely of saidU-shaped spring and adapted when tightened to relieve the initialtension therein, and a supplementary compression spring disposed insurrounding relation upon said screw, said supplementary spring beinginterposed between the ends of said U-shaped spring to augment thetension produced by the latter in the guide bar.

HAROLD O. CADMAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 522,375 Ives July 3, 1894 537,117Ives Apr. 9, 1895 1,384,756 Hambuechen July 19, 1921 1,416,952 GardnerMay 23, 1922 1,862,894 Hughes June 14, 1932 2,169,252 Koether Aug. 15,1939 2,209,711 Young July 30, 1940

